The transport of contaminated liquids by centrifugal pumps presents difficulties not only to the blade wheels of such pumps, but in principle to all parts of the pump within the flow path of the liquid. Such difficulties include, inter alia, the risk of plugging or blocking flow through a portion or even through the entire pump. Current-carrying interior parts, constrictions, and edges are areas of special concern. Accordingly, when designing a centrifugal pump, one always strives to avoid or minimize these problems. However, as a result, the pump housing is relatively large due to the generous flow guidance, which largely eliminates the troublesome effects. This is especially true for submersible motor-driven pumps which have a radial or semi-axial outlet, and are used in pipe shafts where the transport medium must be eventually deflected into the axial direction. These centrifugal pumps are constructed with a very large radius and consequently require a large installation diameter, which in turn creates high construction costs for the pipes receiving these pumps.